term_node migration fails in weird ways if node migration failed

Added a bit of defensiveness to the d6_term_node and d6_term_node_revision migrations. Still needs tests, but I expect this will help.

I worked very, very hard and I think I deserve a test.

A test?

A test.

+++ b/core/modules/taxonomy/src/Tests/Migrate/d6/MigrateTermNodeTest.php
@@ -51,4 +55,28 @@ public function testTermNode() {
+    $node = $this->sourceDatabase->select('node', 'n')
+      ->fields('n')
+      ->condition('nid', 2)
+      ->execute()
+      ->fetchAssoc();
+    $row = new Row($node, $migration->getSourcePlugin()->getIds());

$node does not need to be fully populated, ['nid' => 2] will do.

Other than that, looks good for what it does. I'll repeat what I've said previously, though - we should not have separate term_node* migrations, term references should be migrated as part of the node migration just like any other field. This bug fix holds us over until we address that (I'll open an issue).

Moved the gnarly set-up stuff in testSkipNonExistentNode() into a helper method of MigrateTestBase. I think this is a scenario we may want to test again, so it makes sense to have a helper for that. Also addressed @mikeryan's comment above.

RTBC pending successful automated tests.

Added issue for merging term_node into node migrations: #2597650: Term references should be incorporated into D6 node migration.

Committed and pushed to 8.0.x. Thanks!